1. Field of the Invention
This invention relates to a sheet binding apparatus configured to align sheets and bind them together and, more particularly, having binding means of different types. The invention also relates to an image forming system.
2. Description of the Related Art
Hitherto known well is a sheet binding apparatus configured to align sheets and bind them together in an image forming apparatus such as a copier or a printer.
In such a sheet binding apparatus the sheets may be bound in a so-called “needle binding method” using needles to bind the sheets, or in a so-called “non-needle binding method” using no needles to bind the sheets. In a non-needle binding method, the sheets are pressed, entangling the sheets' fibers and thereby binding the sheets. In another non-needle binding method, holes are cut in a part of each sheet and this part is folded back and passed through the holes of the next sheet, thereby binding the sheets together.
As is disclosed in JP 2015-16970 A, a sheet binding apparatus has a needle binding mechanism and a non-needle binding mechanism, which bind sheets in the needle binding method and the non-needle binding method, respectively. In this binding apparatus, the non-needle binding mechanism is secured at one side of the sheets, and the needle binding mechanism is moved along the side of the sheets. Either the needle binding mechanism or the non-needle binding mechanism is selected and used to bind the sheets.
In the sheet binding apparatus disclosed in JP 2015-16970 A, however, the needle binding mechanism is moved to that side of the sheets, which opposes the side where the non-needle binding mechanism is provided, thereby to achieve maintenance including replenishing needles at the other side of the sheets. Consequently, maintenance must be performed on the non-needle binding mechanism, at the side opposite to the needle binding mechanism, which is laborious.